(CNN) -- After five years of trying to date girls and to conform and conceal his sexuality, 18-year-old Steven Field told his friends and family that he was gay.

Steven Field, now 25, came out to his friends and family when he was 18.

"I wasn't being honest to myself," Field, now 25, said of his closeted high school years in the suburbs of Chicago, Illinois.

Being gay was natural for him, Field, who lives in Washington, said in a Thursday phone interview. "I didn't choose to be gay anymore than straight people choose to be straight."

To those who would disagree with him, Field said, "You don't choose who you love."

Field is not alone in thinking that sexual orientation is a fixed element of a person. Whether homosexuality is innate or whether it is acquired -- the age-old nature versus nurture debate -- has long shaped the political and social discussion over gay rights.

Over the years, the genetically based argument has found increasing support among Americans, according to polls. More and more people now believe that homosexuality is a permanent, immutable part of a person, much like fingerprints or eye color.

According to a CNN/Opinion Research Corp. poll released Wednesday, 56 percent of Americans believe that gays and lesbians could not change their sexual orientation even if they wanted to do so -- the first time that a majority has held that belief regarding homosexuality since CNN first posed the question nearly 10 years ago.

The sampling error for the results is plus or minus 4.5 percentage points.

Six years ago, 45 percent of Americans responding to a CNN/USA/Gallup Poll said gays and lesbians could not change their sexual orientation. And in 1998, the number was 36 percent, according to a CNN/Time poll.

The latest poll results affirmed what many gay and lesbians see as a shift in attitude across the country toward homosexuality. Even in the face of state legislation that denies gays the right to marry or to form civil unions, more Americans are now accepting of homosexuality, gays and lesbians say.

For the Rev. Mel White, the founder and president of faith-based gay rights group Soulforce, the poll results were a "tremendous relief."

"The poll is such good news," White said Thursday. "Over half of America thinks we don't have to be healed from a sickness; suddenly we are OK as we are." Watch gay homeless teens »

The change in thinking among Americans can be attributed to more and more people getting to know gays and lesbians as they come out, White said.

"Once they know us, they will support us," he said, adding that the idea extended to faith-based organizations that currently oppose gay rights, White said.

White, once a ghostwriter for the Revs. Jerry Falwell, Pat Robertson and Billy Graham before coming out in a public sermon in 1993, said the church was the barrier to nationwide acceptance of gays and lesbians.

"Until the church changes, this debate will go on and on and on," he said. "Once the church changes, it'll be over."

But for organizations that say gays and lesbians can become straight, the poll results were discouraging.

This "shows that our reach is not as great as the mainstream media and entertainment industry," said Peter Sprigg, vice president for policy for the Family Research Council.

"People are believing what they are hearing, and it's not the truth," he said, adding that it was disappointing Americans had succumbed to what he called a "myth" that gays and lesbians cannot change. They can change, but it is difficult, he said.

For gay and lesbian organizations, the poll results came as affirmation for the work they do.

"We were really excited to see it," Jean-Marie Navetta, director of communications for Parents and Friends of Lesbians and Gays, or PFLAG, said of the poll.

"It's good to see that this message [being gay is not a choice] is moving to a large number of Americans."

Navetta said she and other PFLAG employees had sensed a swing in attitude toward gays and lesbians. "There are more people that are out as well as [straight] allies that are out," she said, explaining the shift. When people realize "this is about your neighbors and co-workers and friends and family ... the issue becomes a person," she said.

Melissa Fryrear, director of gender issues for Focus on the Family, said she found the results unfortunate -- not only because they run counter to the beliefs of her group but to her personal experience as well.

"I know that homosexuality can be overcome because that's the story of my life," she said. Fryrear said she lived as a lesbian for nearly a decade before becoming a Christian and later "overcoming" her homosexuality through a long process of change and self-examination.

Like Sprigg, Fryrear attributed the poll's results, at least partly, to the media's coverage of the issue. "The truth that people can change has not been represented oftentimes correctly and fairly in the media," she said.

However, she said, people who want to try and become heterosexual would not be dissuaded by those do not believe change is possible. "They're going to make that personal decision to overcome homosexuality regardless," she said.

According to the poll released Wednesday, 36 percent of Americans agree with Fryrear and Sprigg that gays and lesbians can change their sexual orientation.

For Field, the issue of whether he can change or not is irrelevant.

"I think it's important for everyone to be true to themselves," he said. "This is who I am and I'm proud of it."E-mail to a friend